casparianin

Casparianin is a type of protein found in the cell walls of plants, particularly in the endodermis of roots and the exodermis of leaves. It is named after the German botanist Robert Caspary, who first described it in the late 19th century. Casparianin is a member of the pathogenesis-related (PR) protein family, which are induced in response to various biotic and abiotic stresses.

The primary function of casparianin is to act as a barrier, preventing the movement of water and solutes between adjacent cells. This is achieved through the formation of a continuous, impermeable band of callose and suberin, known as the Casparian strip, which surrounds the endodermal cells. This strip is crucial for the selective transport of water and nutrients from the soil into the plant, as it allows water to pass through the cell walls but prevents the passage of solutes.

Casparianin is also involved in the regulation of cell wall metabolism and the response to environmental stresses. It has been shown to play a role in the regulation of cell wall loosening and expansion, as well as in the response to pathogens and other stressors. The expression of casparianin genes is induced by various stimuli, including wounding, pathogen infection, and exposure to abiotic stresses such as drought and salinity.

Casparianin is a highly conserved protein, with homologs found in a wide range of plant species. It is encoded by a small gene family, with multiple members often found within a single genome. The regulation of casparianin expression is complex, involving multiple signaling pathways and transcription factors. The study of casparianin and its role in plant development and stress response is an active area of research in plant biology.